The world population has grown to point where mass production of the foods that we consume is no longer a luxury but a requirement. Local farmers, providing food and food products directly to the marketplace, cannot meet the demands of modern society. The food supply chain now incorporates very large, complex farms and high speed and very high volume processing plants to satisfy the need for mass processing and production of food. Maintaining a safe food supply chain relies on the dedication of those working in the supply chain, the processing plants and also on the third party oversight of various Federal agencies whose regulations support and mandate food safety.
With two major exceptions, the physical process of taking an animal from the farm to the consumer has changed very little over time. The introduction of refrigeration, and the implementation of various chemistries to help maintain sanitary conditions and to control microbiology, has given modern food processors an advantage not enjoyed by food producers of a century ago. Refrigeration and chemical intervention practices have become an integral part of food processing facility operations. These technologies have enabled the high speed, high volume output of the large processing facilities that could not have been possible in times past without significant concern for consumer safety. With large scale and continuous processing methods being employed by large processors of protein products, or any other product that is susceptible to microbiological contamination, the concern for the control of microbiology and the safety of the food supply chain is of paramount importance.
Another concern, as the demand for food products increases, is the impact on natural resources created by this demand. The ecological impact is directly affected by this growth and therefore new processes must be developed to reduce the impact any given process has on the environment. The ecological impact that a food processing plant has on the environment is no longer a passing concern but a major part of operations and planning. Entire processes are built around the control and conservation of natural resources such as water. Older, outdated and less efficient processes are being replaced at significant cost with more efficient and less wasteful processes that maximizes the utility of available resources. No longer can a plant operate without concern for the conservation and sustainability of natural resources. As each step in food processing becomes more efficient, the natural resources required to be used in subsequent steps can be minimized to conserve and sustain our natural resources.
Still another concern in slaughtering and processing plants is unwanted microorganisms that are emitted into the air or are contained on the animal carcass when the animal is processed, such as poultry (i.e., turkey, duck and chicken) during shackling, killing, scalding, and picking areas. The microorganisms that may become airborne or contained on the animal carcass are unwanted in the processing and packing areas of the plant because they can affect product quality and safety. They also pose a potential threat to the health and well-being of the workers in the plant. Still further, such microorganisms can affect down-field processes in a processing plant, posing quality and safety concerns to the ultimate consumer of the poultry product.
To insure that the food supply chain in modern society is maintained at the highest levels of safety for the consumer, the plant's employees, and the overall environment, there are federal agencies that monitor the processors operations so that a continually safe food supply is assured and the environmental impact and utilization of natural resources is as safe and efficient as possible. Modern food processing methods are scrutinized by government agencies to ensure compliance with safe handling and processing guidelines designed to minimize issues of food safety in the supply chain Regulations and routine inspections of systems and processes by Federal agencies such as the USDA, EPA and OSHA, mandate a government-industry alliance that helps ensure that every effort is made to deliver the safest food product possible to the consumer.
Very innovative approaches to the systems and methods used in processing facilities have been implemented to create profits for industry while maintaining low consumer cost of the final product. As new processes are developed, the federal agencies that have jurisdiction over any particular process are called upon to review the new approach and to ensure that the new innovation meets the current guidelines for safety. The higher the processors output, the higher the risk of microbiological contamination, and therefore the more innovative the processor must be to combat this ever present threat to the food chain safety. As new risks are found, federal guidelines become more stringent.
Large scale refrigeration systems, used to help control microbial growth in various processing applications, have helped the food processing industry to remain in compliance with food safety goals. Refrigeration applications and processes are implemented at various locations in the processing operation to ensure maximization of microbiology control and shelf life. Depending on the particular product being processed—beef, pork, poultry and fish for example—and the particular operation taking place, various methods of achieving this reduction in product temperature are employed. In industrial processing of poultry, for example, immediately after slaughter, bleed out, hot water immersion, feather removal and viscera withdrawal, poultry carcasses have to be chilled to reduce their temperature from approximately 40° C. to 4° C., which contributes to food safety. While poultry carcasses may undergo air chilling after evisceration, in countries such as the United State and Brazil, two of the biggest poultry producers in the world, poultry carcasses usually undergo immersion chilling after evisceration by submersing the poultry carcass in large chilled water bath tanks.
Immersion chilling has a benefit of an increased “washing effect” which lowers the total microbial load on the birds; however, it is also a potential place for cross contamination to occur. In order to control microbiology in chiller tanks, it is a typical practice to add specialized chemistry to the tanks throughout the processing day. This specialized chemistry, known in the industry as intervention solutions kill or provide a log10 reduction in the amount of any unwanted microorganisms. There are several antimicrobials that are approved and effective for use in the chiller to decrease pathogens, including, for instance, chlorine, peroxyacetic acid (“PAA”), CPC, organic acids, TSP, acidified sodium chlorite and chlorine dioxide. Because chiller tanks are often quite voluminous, the amount of antimicrobials needed can be quite high to provide a desired log10 reduction in the amount of any unwanted microorganisms.
PAA, which is also sometimes called peroxyacetic acid, is a peroxycarboxylic acid and is a well known chemical for its strong oxidizing potential, has the molecular formula CH3COOOH, and has a molecular structure as follows:
An equilibrium peroxyacetic acid solution is produced from an equilibrium mixture of hydrogen peroxide, acetic acid and water (“equilibrium PAA solution”), which often uses an acid catalyst, e.g., sulfuric acid.
U.S. Pat. No. 5,632,676, which pertains to the application of equilibrium PAA solutions to fowl at an application concentration of about 100 ppm to about 2000 ppm, discloses such equilibrium solutions having a pH around 3.
Beyond equilibrium PAA solutions, other equilibrium peroxycarboxylic acid (“PCA”) solutions can also be produced from a similar equilibrium mixture of hydrogen peroxide, water and the respective acid. Such commercial products also often contain stabilizers and/or catalysts, like 1 Hydroxyethylidene 1-1 diphosphonic acid (HEDP), various phosphate salts, organic or inorganic acids, etc., to facilitate production and storage stability of the product. Hydrogen peroxide is always present in excess in the natural equilibrium formulation of PAA solutions (and other equilibrium PCA solutions).
As such, there is a need in the industry to efficiently and cost-effectively reduce microbial contamination of poultry carcasses during poultry processing. There is also a need in the industry to efficiently and cost-effectively minimize the amount of unwanted microorganisms on a poultry carcass during processing prior to the immersion chilling step.